Design of Capacitive Power Transfer Using a Class-E Resonant Inverter

Abstract

This paper presents a capacitive power transfer (CPT) system using a Class-E resonant inverter. A Class-E resonant inverter is chosen because of its ability to perform DC-to-AC inversion efficiently while significantly reducing switching losses. The proposed CPT system consists of an efficient Class-E resonant inverter and capacitive coupling formed by two flat rectangular transmitter and receiver plates. To understand CPT behavior, we study the effects of various coupling distances on output power performance. The proposed design is verified through lab experiments with a nominal operating frequency of 1 MHz and 0.25 mm coupling gap. An efficiency of 96.3% is achieved. A simple frequency tracking unit is also proposed to tune the operating frequency in response to changes in the coupling gap. With this resonant frequency tracking unit, the efficiency of the proposed CPT system can be maintained within 96.3%-91% for the coupling gap range of 0.25-2 mm.

Design and Analysis of Capacitive Power Transfer System with and without the Impedance Matching Circuit

“…This can be clearly shown in [15] whereby in order to achieve efficiency of 98.44%, the gap between the capacitive coupling is as near as less than 1mm for basic circuit configuration with class E inverter. Besides, there was also an analysis regarding gap distance which concluded that as distance increases, the efficiency of the system represented by output voltage is tremendously decreases exponentially shown in Figure 2.…”

“…Moreover, as Table 1 and Table 6 to be compared, there are different values for the same components of series inductor L, the shunt capacitor Cs, and the series capacitor C 1 and C 2 . This is due to different equations that have been used to calculate the components' values, as displayed in Equations (8) to (15).…”

“…As proved and explained in previous sections, the aluminium sheets' size for the CPT system is getting smaller by the existence of an impedance matching network, as shown in Figure 12. This is due to the recalculation of components values by using equations (8)(9)(10)(11)(12)(13)(14)(15) and by adding an extra capacitor as impedance matching, the desired output is achieved and maintained with smaller size of capacitive plates. The value of the capacitive coupling is initially 0.21m x 0.24m, which is equal to 4.07nF.…”

“…Figure 2. Output voltage decreases tremendously and distance increases [15] Realising the issue of system's efficiency, this work intended to propose class E circuit with the addition of an impedance matching circuit. This circuit is mainly added to improve efficiency of the particular system by stabilising it and eventually sustain higher output power.…”

Analysis of the Influence of Compensation Capacitance Errors of a Wireless Power Transfer System with SS Topology

“…It has been widely used in traffic, consumer electronics, underwater, mining equipment, and so on. Compared to the traditional plug-in power supply system, the wireless power transfer (WPT) system can achieve mechanical and electrical isolation, minimize cable and socket applications, and ensure safe operation in harsh environments [1,2]. Especially in electric bus and energy storage tram charging, the WPT primary side coil winding can be buried under the existing platform, and achieve station charging.…”